725 research outputs found
Lasing oscillation condition and group delay control in gain-assisted plasmon-induced transparency
A gain-assisted plasmonic waveguide with two detuned resonators is
investigated in the plasmon-induced transparency window. Phase map is employed
to study power transmittance and group delay for varying gain coefficients and
frequency detunings of the two resonators. The gain coefficient for lasing
oscillation condition is analytically shown to vary quadratically with the
frequency detuning. In the amplification regime below the lasing threshold, the
spectrum implies not only large group delay, but also high transmittance and
narrow linewidth. This is in contrast to those in the loss-compensation regime
and the passive case in which there always exists a trade-off between the
linewidth and the peak transmittance.Comment: 15 pages, 4 figure
Transplantation of a Peripheral Nerve with Neural Stem Cells Plus Lithium Chloride Injection Promote the Recovery of Rat Spinal Cord Injury
Transplantation of neural stem cells (NSCs) holds great potential for the treatment of spinal cord injury (SCI). However, transplanted NSCs poorly survive in the SCI environment. We injected NSCs into tibial nerve and transplanted tibial nerve into a hemisected spinal cord and investigated the effects of lithium chloride (LiCl) on the survival of spinal neurons, axonal regeneration, and functional recovery. Our results show that most of the transplanted NSCs expressed glial fibrillary acidic protein, while there was no obvious expression of nestin, neuronal nuclei, or acetyltransferase found in NSCs. LiCl treatment produced less macrosialin (ED1) expression and axonal degeneration in tibial nerve after NSC injection. Our results also show that a regimen of LiCl treatment promoted NSC differentiation into NF200-positive neurons with neurite extension into the host spinal cord. The combination of tibial nerve transplantation with NSCs and LiCl injection resulted in more host motoneurons surviving in the spinal cord, more regenerated axons in tibial nerve, less glial scar area, and decreased ED1 expression. We conclude that lithium may have therapeutic potential in cell replacement strategies for central nervous system injury due to its ability to promote survival and neuronal generation of grafted NSCs and reduced host immune reaction
Validation and interpretation of three-dimensional configuration of a magnetic cloud flux rope
One "strong" magnetic cloud (MC) with the magnetic field magnitude reaching
40 nT at 1 au during 2012 June 16-17 is examined in association with a
pre-existing magnetic flux rope (MFR) identified on the Sun. The MC is
characterized by a quasi-three dimensional (3D) flux rope model based on in
situ measurements from the Wind spacecraft. The magnetic flux contents and
other parameters are quantified. In addition, a correlative study with the
corresponding measurements of the same structure crossed by the Venus Express
(VEX) spacecraft at a heliocentric distance 0.7 au and with an angular
separation in longitude is performed to validate the MC modeling
results. The spatial variation between the Wind and VEX magnetic field
measurements is attributed to the 3D configuration of the structure as featured
by a knotted bundle of flux. The comparison of the magnetic flux contents
between the MC and the source region on the Sun indicates that the 3D
reconnection process accompanying an M1.9 flare may correspond to the magnetic
reconnection between the field lines of the pre-existing MFR rooted in the
opposite polarity footpoints. Such a process reduces the amount of the axial
magnetic flux in the erupted flux rope, by approximately 50\%, in this case.Comment: Submitted to Ap
Combining interscalene brachial plexus block with intravenous-inhalation combined anesthesia for upper extremity fractures surgery: A randomized controlled trial
AbstractBackground: A parallel-group randomized controlled trial (RCT) was conducted to evaluate the effect of combining the interscalene brachial plexus block (IBPB) with Intravenousâinhalation combined anesthesia to isolated Intravenousâinhalation anesthesia in the upper extremity fractures surgery of elderly patients. Methods: One hundred elderly patients who underwent upper extremity surgery were randomly assigned to received isolated Intravenousâinhalation combined anesthesia (group CI, n = 50) and IBPB associated with Intravenousâinhalation combined anesthesia (group NB, n = 50). Associated side effects, recovery time after operation, as well as the dose of intraoperative vasoactive agents and auxiliary drugs were noted. Results: The two groups were not significantly different in gender (P = 0.539), ages (P = 0.683) and weight (P = 0.212). Five patients (10%) in the group NB and 17 patients (34%) in the group CI suffered from preoperative hypotension (P = 0.004). Besides, lower incidence of other adverse effects such as mental stress, incision pain and hypertension were also found in the group NB; however, the differences were not statistically significant (P > 0.05). The consumption of general anesthetics in the group NB was significantly less than that of the group CI (propofol, P = 0.004; lsoflurane, P < 0.001), and the recovery time of the group NB was significantly shorter than that of the group CI (P = 0.020). Conclusion: Combining IBPB with Intravenousâinhalation combined anesthesia in elderly patients hold a greater potential for upper extremity fractures surgery due to its improved clinical effectiveness and fewer side effects
Chondrosterins AâE, Triquinane-Type Sesquiterpenoids from Soft Coral-Associated Fungus Chondrostereum sp.
The marine fungus Chondrostereum sp. was collected from a soft coral Sarcophyton tortuosum from the South China Sea. This fungus was cultured in potato dextrose broth medium and the culture broth was extracted with EtOAc. Five new triquinane-type sesquiterpenoids, chondrosterins AâE (1â5), and the known sesquiterpenoid hirsutanol C (6), were isolated. The structures were elucidated mainly on the basis of NMR, MS, and X-ray single-crystal diffraction data. Chondrosterin A (1) showed significant cytotoxic activities against cancer lines A549, CNE2, and LoVo with IC50 values of 2.45, 4.95, and 5.47 ÎŒM, respectively
Hierarchical chirality transfer in the growth of towel gourd tendrils
Chirality plays a significant role in the physical properties and biological functions of many biological materials, e.g., climbing tendrils and twisted leaves, which exhibit chiral growth. However, the mechanisms underlying the chiral growth of biologic
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